In 2017, a security vulnerability present in certain computer systems was discovered. A demonstration of this security vulnerability involved launching an attack on a computer system using Direct Memory Access (DMA) over an external expansion card slot of a host machine to bypass a login screen on the Linux operating system executing on the host machine. Direct Memory Access (DMA) is an approach that allows an input/output device to send or receive data to or from the main memory of the host machine in a manner that bypasses the CPU of the host machine to speed up memory operations.
As a result of the discovered security vulnerability to the Linux operating system, the industry has collectively concluded that an operating system must protect itself using virtualization technology to block DMA-based attacks from malicious devices.